Time: 2021-02-11 09:30-10:30 ((UTC00:00) Edinburgh Video of the talk: https://youtu.be/sMWOQNfYIUw Speaker: James Wood, Strathclyde U Abstract: The metatheory of simple type systems presented using de Bruijn indices is well understood. We know to follow the principle that variable binding is the only interaction between the context and typing rules other than the variable rule. From […]

Jesse Sigal, University of Edinburgh. Automatic differentiation (AD) is an important family of algorithms which enables derivative based optimization. We show that AD can be simply implemented with effects and handlers by doing so in the Frank language. By considering how our implementation behaves in Frank’s operational semantics, we show how our code performs the […]

Time: December 10th, 10 am. Speaker: Sam Lindley, Senior Consultant Abstract: In software systems effects are pervasive, e.g.: concurrency, distribution, exceptions, I/O, and nondeterminism. Effect handlers are a general programming feature that can be used for modularly implementing all of these effects and more. They were introduced by theoretical computer scientists studying the theory of […]

Our intern Bruce Collie, together with Jackson Woodruff, and Michael O’Boyle have won the best paper award at GPCE this year for their paper Modeling Black-Box Components with Probabilistic Synthesis. Paper : https://arxiv.org/abs/2010.04811 Talk video: https://conf.researchr.org/details/gpce-2020/gpce2020/1/Modeling-Black-Box-Components-with-Probabilistic-Synthesis Congratulations!

Technical Talk: Syntactic reasoning for digital circuits using graphs Dan R. Ghica When: Thursday, November 19, 10am (Edinburgh) Abstract: I will present a general diagrammatic theory of digital circuits, based on connections between monoidal categories and graph rewriting. The main achievement of the paper is conceptual, filling a foundational gap in reasoning syntactically and symbolically […]

 A graphical language for closed monoidal categories, by Dan Ghica. Diagrams, schematics, blueprints and so on play an important role in engineering, architecture, construction, and other activities where projects need to be formally specified. In mathematics the role of diagrams has been, at least until recently, mostly that of illustrating concepts, rather than specifying formally […]

Programming language Virtual Machines (VMs) must make many assumptions about how programs typically operate in order to effectively optimise them. We less commonly consider the many assumptions that VM developers and researchers hold about how VMs operate and the context within which they operate. In this talk, I will present a number of partly, or […]

On Tuesday 27th October at 1:15pm (UK time), Mario Alvarez-Picallo, The Difference Lambda Calculus Abstract: Cartesian difference categories are a recent generalisation of Cartesian differential categories which introduce a notion of “infinitesimal” arrows satisfying an analogue of the Kock-Lawvere axiom, with the axioms of a Cartesian differential category being satisfied only “up to an infinitesimal […]

by Dan R. Ghica We propose a core calculus for programming languages with effects, interpreted using a hypergraph-rewriting abstract machine. The intrinsic calculus syntax and semantics only deals with the basic structural aspects of programming languages: variables, names, and thunks. Everything else, including function abstraction and application, must be provided as extrinsic operations with associated […]

by Mario Alvarez Picallo When you hear the word ‘derivative’, differential calculus immediately comes to mind. This is, however, far from the only place where one can find them! Many ad-hoc notions of derivative have popped up over the years, in fields as disparate as incremental computation and digital circuits. In this talk we introduce […]